1. Field of the Invention
This invention relates to an electric motor or gasoline engine driven pruner by which to cut otherwise inaccessible trees and shrubs and having collapsible drive shaft and drive shaft housing assemblies.
2. Prior Art
Conventional tree and shrub pruners which are known to the applicant are typically non-motor driven devices that require high degrees of strength and/or force to cut relatively thick branches and limbs. Moreover, such assemblies usually require the expenditure of large amounts of time and energy to complete most pruning jobs. By way of example, a hook saw has long been used to cut low lying tree branches. Another common pruner has a scissors-like cutting head which is remotely controlled by means of an elongated connecting pull rod. Still another well-known pruner is air-driven and, therefore, requires a constant and readily available source of air supply. Hence, such devices may be undesirably characterized by relatively poor efficiency and increased difficulty of operation.
What is more, many of the aforementioned pruners are not sutiable to permit the remote cutting of trees and shrubs. That is, a ladder, stool, or the like is frequently needed to permit the user to reach an otherwise inaccessible branch or limb. Consequently, a ladder or stool may provide an unsafe environment for the user or necessitate the presence of another individual to lend assistance or provide support. However, even with a reach extending ladder or stool, the user may still be unable to penetrate dense branches and limbs without reducing cutting control or possibly injuring his hands and arms. Therefore, such devices are also undesirably characterized by inconvenience and lack of cutting accuracy.
No collapsible pruner arrangement is known in which a rotatable, telescoping drive shaft assembly is surrounding by a telescoping housing assembly. The problems that are overcome by the present invention include preventing the drive shaft and housing assembly sections from pulling apart at such times when the pruner is fully extended to reach high branches and limbs. Moreover, no rotation may be imparted to the housing when the rotatble drive shaft is rotated therewithin. What is more, a bushing/insulator is needed by which to separate the rotatable drive shaft from the housing while permitting the drive shaft and housing assemblies to slide therepast when the pruner is moved to the expanded or collapsed conditions.
Examples of conventional pruners are available by referring to one or more of the following U.S. Pat. Nos.: 2,703,928, Mar. 15, 1955; 3,731,380 May 8, 1973; 3,731,382 May 8, 1973; 4,048,722 Sept. 20, 1977; 4,207,675 June 17, 1980; 4,341,017 July 27, 1982.